forensic comp study

Forensic Science is the...

application of science to law

who is the father of forensic toxicology?

Mathieu Orfila

Who discovered identification through fingerprints?

Francis Galton

When are fingerprints formed in humans?

During the 12th week of gestation

What does "latent" mean?

hidden or invisible

Who created the ABO Blood system?

Karl Landsteiner (1909)

Who applied the comparison microscope in ballistics?

Calvin Goddard

What does NIBIN stand for?

National Integrated Ballistics Information Network

What is Locard's principle of exchange?

when a person comes into contact with an object or another person, a cross-transfer of physical evidence can occur

Frye standard

"general acceptance" by the relevant scientific community

Federal Rules of Evidence (3)

1. Testimony based on sufficient facts or data
2. Testimony is a product of reliable principles and methods
3. Witness has applied methods reliably to facts of case

Daubert Standard (5)

1. theory has been tested
2. theory has been published/reviewed
3. rate of error associated w/ technique
4.standards exist
5. theory generally accepted in relevant scientific community

What are the 6 basic positions for crime scene search personnel?

-team leader
-photographer
-sketcher
-evidence custodian
-evidence recovery personnel
specialists

What are the primary tasks of first responders on scene? (4)

1. detain any potential subjects
2. Render medical assistance to those in need
3. Dont destroy, alter, or add evidence to the scene
4. prevent others from altering the scene

what is transient evidence?

evidence that can be can be changed or lost (example: odor/ temp/weather)

a crime scene sketch should include: (7)

-case identifier
-date/time/location
-weather and lighting
-identity and assignments of personnel
-dimensions of room, furniture, doors, windows
-distance between objects, persons, bodies, entrances, and exits

12 Stages of a crime scene

1. preparation
2. approach scene
3. secure/protect scene
4. preliminary survey
5. evaluate physical evidence possibilities
6. narrative description
7. depict scene photographically
8. diagram/sketch scene
9. conduct detailed search
10. record/collect physical evidence
11. conduct final survey
12. release scene

how far is the crime scene perimeter established?

1.5 x the distance from the center of the scene to the furthest known piece of evidence

Crime Scene Search Patterns

spiral,
strip/line,
grid,
zone/quadrant,

three types of crime scene photos

overall
medium
close up

scene photography needs to include:

entry/exits
overall,medium,close up
surrounding areas/neighborhood
victims/crowds/vehicles

which type of scene photo is taken with and without scales?

close ups

paper packaging is used for what type of evidence?

biological materials

what evidence are clean paint cans used to package?

bomb/arson evidence

primary transfer

Transfer of trace evidence from its original location to a different location

secondary transfer

the transfer of evidence such as a fiber from a source to a person, and then to another person

some ways to collect trace evidence

scraping
vacuum
tape lifting

three areas of a hair shaft

cuticle (outside)
cortex
medulla (middle)

where is hair pigment found?

cortex

what are the cross-section hair shapes for:
-Caucasian
-negroid
-mongoloid

C: oval
N: flattened
M: round

what are the 2 growth stages or hair?

anagen (80-90%)
telogen (8-18%)

how much does hair grow each month?

1/2 inch

what are the 2 types of DNA found in hair

mtDNA and nuclear

mtDNA is found in \_____ hair and nuclear/mtDNA is found in \______ hair

mtDNA- telogen
Nuclear- anagen forcibly removed

2 types of fibers

natural and synthetic

which type of fiber has scales?

natural fibers

which type of glass has layer to prevent full breaking?

non-tempered

two types of fractures in glass

radial (linear)
concentric (circular)

cratering from a bullet occurs on \_______ wound

exit

soil has three different properties

physical
chemical
microscopic(biological)

can impression evidence be 2D & 3D?

yes!

the Nat'l Automotive Paint File (NAPF) includes \_____ vehicles

USA vehicles

The Paint Data Query (PDQ) includes \________ vehicles

USA + World

What does IAFIS stand for?

Integrated Automated Fingerprint Identification System

serology is the ..

science of body fluid identification and characterization

What is the difference between a presumptive test and a confirmatory test?

a confirmatory test will test positive for one substance and only that substance

blood DNA is found in \_______

white blood cells

presumptive tests for blood

phenolphthalein
hemastix
luminol

where in cells is DNA found? which one hold more DNA?

mitochondria
nucleus

Mito hold more

what is the STR loci standard for testing DNA?

13

what is the confirmatory test for blood?

Takayama / hemochromogen crystals

semen is composed of (2) and where is the DNA found?

Spermatozoa (DNA here)
seminal fluid

which DNA is found in telogen hair?

mtDNA

3 Decomposition processes

putrefaction (insects)
mummification (dry)
saponification (wet)

What is lividity (livor mortis)

blood settling because the heart stopped circulating

entomologist estimate...

the time of initial insect colonization in postmortem bodies

what is the fingerprint identification equation?

uniqueness + permanence \= individualization

what are the 3 fingerprint patterns & their %

loop - 65%
whorl - 30%
arch - 5%

what are the 3 different types of fingerprint substrates?

latent
patent
plastic

what is the processing test for fingerprints on paper?

ninhydrin

what does ACE-V stand for?

analysis, comparison, evaluation, verification

Explain level 1,2,3 detail in ACE-V

1- ridge flow
2-ridge detail (galton features)
3- ridge attributes ( width, pores)

Galton Features

bifurcation
dot
ridge ending
island
enclosure

how much of a fingerprint is needed to make an ID?

1/4th inch

4 types of whorls

plain
central pocket loop whorl
double loop whorl
accidental whorl

2 types of arches

tented arch
plain arch

bifurcations usually open ....

towards delta

differences in male/female skull

MALE: square chin, large canines, extreme supra-orbital ridge(eyebrow)
FEMALE: smaller skull, small round chin, slight supra-orbital ridge

spherical blood spatter occurs closer to \_____*

90*

what is the parabola effect?

blood does not travel in a straight line

low velocity spatter is created by a ....

force traveling at 5 feet per second

medium velocity spatter is created by a ...

force traveling at 5 to 25 feet per second and producing drops with diameters between 1 -4 mm.

high velocity spatter is created by a...

force traveling at 100 feet per second or faster and producing drops with diameters less than 1 millimeter.

which velocity spatter speed is associated with Blunt force trama?
with gunshot?

BFT- medium
GUN- high

cast-off stains help determine...

number of blows

cast-off stains usually occur as...

linear trials

blood begins to skeletonize/ dry in?

50 seconds

what methods are used to collect dry blood? wet blood?

dry- scraping
wet- cotton swab

Best predictor of future behavior

past behavior

what type of mass murderer cannot be profiled?

school shooter/drive by shooting

MO vs signature

MO: Actions that are needed to complete the crime
SIGNATURE: actions taken to enjoy the crime

overkill in a murder suggests...

that the individuals knew each other

3 goals of profiling

1. provide possible behavioral characteristics
2. suggest investigative strategies
3. suggest types of belongings to be in the suspect's possession

What does ViCAP stand for?

Violent Criminal Apprehension Program

ViCAP is a database for: (4)

-solved/unsolved crimes
-missing persons
-unidentified bodies
-sexual assault cases

Mass murder vs Serial murder

MASS: killing of 3+ ppl in one location
SERIAL: killing 3+ ppl on separate events with dormant period

3 types of body disposals

concealed
displayed
dumped

About how many paraphilias are there?

411

4 types of rapists

power reassurance
power assertive
anger retaliatory
sadistic

which is the most common type of rapist

power reassurance

3 different types of rapist approach

-con
-surprise
-blitz

3 stages of grooming

1. targeting stage
2. nonsexual touching stage
3. sexual touching stage

lands are \________
grooves are \_______

raised
depressed

if a gun barrel has 6 lands, it will have \___ grooves

6

2 types of gun barrels

conventional (lands)
polygonal (smooth)

3 conclusions when doing forensic exams

identification
elimination
inconclusive

What is the equation for determining an angle of impact?

Sin^-1 (w/l)
width divided by length, then press sin^-1

what are the different types of serial number applications?

dot matrix
laser engraved
stamped

what is the difference between specular and diffuse reflection?

specular \= smooth surface
diffuse\= rough surface

what are the three sections of a palm print?

interdigital
thenar
hypothenar